The index has closed higher the past 11 sessions. If it closes up today it will mark the longest streak of gains since the index's inception in January 1984, according to Thomson Reuters Eikon data.

The FTSE 100 opened lower but reversed course to inch 0.2 percent higher by afternoon trading as sterling slid after data showed the UK trade deficit widened.

A weak currency has brightened the earnings outlook for UK blue chips, which get much of their revenue offshore.

However, the index's 3.4 percent drift higher since the latest string of gains began on December 21 is relatively muted compared with prior streaks. Its last 11-day winning streak in July 2009 saw the index rise 11.1 percent.

"The FTSE has not exploded higher, it has inched higher," said Michael Hewson, CMC Markets analyst.

Gold mining stocks Fresnillo (>> Fresnillo Plc) and Randgold Resources (>> Randgold Resources Limited) were the best performing stocks through the latest rally, up 28.8 percent and 18.4 percent respective. Persimmon (>> Persimmon plc), Glencore (>> Glencore PLC) and Anglo American (>> Anglo American plc) round out the top five.

At the other end of table, bruised retailer Next PLC (>> NEXT plc) is the worst performing stock on the index, down 16.4 percent since Dec 21, followed by a 3 percent declines for Marks & Spencer (>> Marks and Spencer Group Plc) and Rolls Royce (>> Rolls-Royce Holding PLC).

(Editing by Vikram Subhedar and Tom Heneghan)

By Helen Reid